Performance Of Nanolubricants Research Articles

Grindability of titanium alloy using cryogenic nanolubricant minimum quantity lubrication

The defect suppression of titanium alloy disturbed by low thermal conductivity is an urgent problem in grinding. The existing green manufacturing processes such as Nanolubricant minimum quantity lubrication (NMQL) and cryogenic air cooling are unsatisfactory due to insufficient cooling or lubrication performance. Cryogenic NMQL (CNMQL) is a new approach that utilizes the heat transfer capacity of cryogenic air and antiwear/antifriction performance of nanolubricant. However, the lack of grindability analysis and in-depth mechanism explanation limits the optimization and application of CNMQL. In this research, the calculation formulas for the Energy ratio coefficient of the cooling medium (Rm) and Defect ratio (Dr) of workpiece surface were established to evaluate Ti-6Al-4V grindability based on other common parameters, including force, temperature, surface roughness, workpiece and debris morphology. Results show that the lowest grinding force (tangential force is 46.8 N, normal force is 61.4 N), grinding peak temperature (151.2 °C), and surface roughness value (Ra = 0.468 μm) are obtained by CNMQL, compared with NMQL and cryogenic air cooling. The Rm in CNMQL is 36.4 %, which is 68.5 % higher than that of NMQL. The Dr value under CNMQL is 2.67 %, which is 84.5 % lower than cryogenic air cooling and 69.2 % lower than NMQL. Cryogenic nanolubricant displays excellent grinding performance due to its higher viscosity and shows significant improvement of convective heat transfer capacity. The critical cutting depth and plastic accumulation are significantly reduced therefore resulting in fewer surface defects.

Comparative rheological study on hybrid nanofluids with the same structure of MWCNT (50%)-ZnO(50%)/SAE XWX to select the best performance of nano-lubricants using response surface modeling

In engineering topics, knowing about the behavior of fluids has always been important and can play an important role in advancing the industry. Therefore, in recent years, many scientific and research fields have addressed this issue. In this study, for the first time, the rheological behavior of hybrid nano-lubricants containing same percentage of ZnO and MWCNT nanoparticles in SAE50, SAE40 and 5W50 base fluids are statistically and comprehensively investigated. Analysis shows that the studied nano-lubricants follow non-Newtonian behavior in all conditions. By adding nanoparticles to 5W50 base oil at a volume fraction of φ = 1% (highest φ) and temperature of T = 5 °C, the viscosity increased about + 30%, which is the highest viscosity increase among the studied nano-lubricants. On the other hand, MWCNT-ZnO (50:50)/SAE50 nano-lubricant at T = 25 °C had a viscosity difference of − 43.10, which is a significant reduction in viscosity. In addition to the experimental results, the response surface methodology (RSM) applied and a Quartic model was used to model the viscosity behavior with an accuracy of R-Squared = 0.9996 in the form of a mathematical correlation. The range of deviation was − 3.82 % < MOD < 4.40 % and the 22.15 % highest sensitivity was occurred at φ = 1% and T = 50 °C. Competitive comparison and determination of one of the studied nano-lubricants as optimal and desirable nano-lubricants, can have applications such as cooling and lubrication in industries that are face with energy loss due to oil pumping, prevent friction between parts, and brings economic cost savings.

Tribological evaluation of piston ring/cylinder liner assembly in automotive engines using GNP as a lubricant additive

Friction and wear are the main causes of energy dissipation in automotive engines. To minimize the frictional power losses, it is extremely important to improve the tribological characteristics of ring/liner assembly which accounts for almost 40–50% frictional power losses. The present study attempts to mitigate friction and wear of the ring/liner tribo-pair using GNP/SAE 15W40 nano-lubricant. To simulate the ring/liner interface, the tribological performance of nano-lubricants was assessed using a tribometer based on ASTMG181 standard under various operating conditions. The coefficient of friction (COF) and wear rate lowered using graphene nano-lubricants (GNL). The tribological results showed that friction coefficient, wear rate, and surface roughness of piston ring improved in the range 17.71%–42.33%, 25%–40.62%, and 61%, respectively, under GNL lubricating conditions during the boundary lubrication. Further, the characterization of wear tracks of piston ring and cylinder liner confirmed tribo-film formation on worn surfaces resulting in decreased COF and wear rate.

Investigation on tribological properties of used engine oil with graphene

The present work concentrate on the improvement in physico-chemical, and tribological properties of used engine oil using graphene nanoparticles. The used engine oil (15W40) has been collected from heavy earth moving machines (HEMM) of coal mines. The graphene nanoparticles have been used for the preparation of nanolubricants and the properties are compared with unused oil. Kinematic viscosity, viscosity index (VI) and density have been measured to examine the physico-chemical properties of nanolubricants and observe the improvements. The stable chemical structure of nanolubricants has been found with Fourier transform infrared spectroscopy (FTIR). The performance of nanolubricant has been found by measuring wear and friction coefficient between grey cast iron contacts and observed the significant reduction in wear and friction compared to used oil. The same has been validated by measuring the wear scar with the help of optical microscopy and electron dispersive X-ray spectroscopy. The life of the used oil has been enhanced with the addition of nanoparticles.

Performance of nanolubricants containing MoS2 nanotubes during form tapping of zinc-coated automotive components

The paper presents the first use of nanolubricants containing MoS2 nanotubes for form tapping of zinc-coated steel. MoS2 nanotubes are known for their superb low frictional, anti-wear and extreme pressure properties and have shown a promising performance as nanolubricant additive in many machining and forming applications. However their interfacial interaction with zinc-coated components commonly used in automotive applications and their synergisms and antagonisms with currently used additives in forming oils are two crucial aspects that have not been addressed so far. The assessment of these synergies is of uttermost importance for developing future nanofluid minimum quantity lubrication formulations, since despite their extraordinary performance, MoS2 nanotubes are not able to fulfil all the roles expected from a forming oil. To this end, this paper aims to investigate the performance of MoS2-based nanolubricants in combination with representative forming oil additives. The threads are perform using a form tapping unit with customized data acquisition on zinc-coated steel, as a representative part in automotive applications. The performance of the nanolubricants is thoroughly investigated using advanced analytic methods with the aim of revealing the underlying interface interaction mechanisms for the observed torque behaviour and resulting thread morphology and sub-surface hardness. The results show that MoS2 nanotubes are able to interact and form a tribofilm in Zn coated surfaces that leads to a superb friction performance. In combination with oil additives, MoS2 based nanolubricants have a particularly positive synergy with extreme pressure additives in terms of friction reduction, sub-surface hardening and thread morphology. On contrary, the lowest synergy is achieved in the presence of dispersants, leading to higher torques during form tapping and higher sub-surface hardness in the formed threads.

Characterization of Al2O3-SAE 15W40 engine oil nanolubricant and performance evaluation in 4-stroke diesel engine

This work aims to characterize Al2O3-SAE 15W40 engine oil nanolubricant and its performance evaluation in 4-stroke diesel engine. Field emission scanning electron microscope (FESEM) images of nanoparticle reveal the spherical morphology of nanoparticle and Fourier transform infrared spectroscopic results show chemical stability of nanolubricants. Dynamic light scattering test display the presence of mild agglomeration of particles in nanolubricants, further FESEM images of dispersed nanoparticles re-confirms it. Density and viscosity of nanolubricants are measured with varying particle volume fraction and temperature. The overall performance of nanolubricant is tested on a 4-stroke diesel engine. The nanolubricant with 0.3% volume fraction of Al2O3 nanoparticles shows less frictional power loss and hence higher brake thermal efficiency as compared to other nanolubricants.